companionway ladder dimensions?? please help!!

We are rebuilding the interior of our boat, redesigning the galley/nav area. In trying to make the best use of space, the thing that keeps frustrating me is the companionway ladder. I do not want it to be too difficult to use (especially since we have a 6-yr-old.) But I don't want it to be too big and waste precious space.

I know that regular house architects can consult a big book of Architectural Standards for dimension help. Is there anything similar for sailboat interior design????

Anyone know what the minumum step depth should be for an open ladder , and for a step with a sold back? Best space between steps? Minimum step width? Best ladder pitch (esp to be able to descend without turning around...)

Any advice much appreciated.

THANK YOU!

[james_r]

The following is paraphrased from Skene's Elements of Yacht Design and is a method that has worked for me:

1.Divide the vertical distance between deck and cabin sole into equal spaces less than 12 ". From 9" to 11" is fine. A steeper ladder should be at the top of this range, a sloping ladder at the bottom. It's important that there be nothing unexpected in a ladder. All steps should be equally spaced.

2.The top step should project forward 9", each one therafter 5". Each step should be at least 6"deep so that it projects 1" under the previous step.

3. The width of the ladder can be as narrow as 15" but 18" is better. Don't forget to put hand holes in the side pieces near the top of the ladder.

If you work in metric multiply the above dimensions by 2.54 to get cm.